1、Designation: E704 13Standard Test Method forMeasuring Reaction Rates by Radioactivation of Uranium-2381This standard is issued under the fixed designation E704; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers procedures for measuring reac-tion rates by assaying a fission product (F.P.) from the fissionreaction23
3、8U(n,f)F.P.1.2 The reaction is useful for measuring neutrons withenergies from approximately 1.5 to 7 MeV and for irradiationtimes up to 30 to 40 years.1.3 Equivalent fission neutron fluence rates as defined inPractice E261 can be determined.1.4 Detailed procedures for other fast-neutron detectors a
4、rereferenced in Practice E261.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of t
5、his standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E170 Terminology Relating to Radiation Measurements andDosimetryE181 Test Methods for Detector Calibration and Analysi
6、s ofRadionuclidesE261 Practice for Determining Neutron Fluence, FluenceRate, and Spectra by Radioactivation TechniquesE262 Test Method for Determining Thermal Neutron Reac-tion Rates and Thermal Neutron Fluence Rates by Radio-activation TechniquesE320 Test Method for Cesium-137 in Nuclear Fuel Solut
7、ionsby Radiochemical Analysis (Withdrawn 1993)3E393 Test Method for Measuring Reaction Rates by Analy-sis of Barium-140 From Fission DosimetersE705 Test Method for Measuring Reaction Rates by Radio-activation of Neptunium-237E844 Guide for Sensor Set Design and Irradiation forReactor Surveillance, E
8、 706 (IIC)E944 Guide for Application of Neutron Spectrum Adjust-ment Methods in Reactor Surveillance, E 706 (IIA)E1005 Test Method for Application and Analysis of Radio-metric Monitors for Reactor Vessel Surveillance, E 706(IIIA)E1018 Guide for Application of ASTM Evaluated CrossSection Data File, M
9、atrix E706 (IIB)3. Terminology3.1 Definitions:3.1.1 Refer to Terminology E170.4. Summary of Test Method4.1 High-purity238U ( 1 MeV)fluence rate of 1 1011cm2s1provided the238U is shieldedfrom thermal neutrons (see Fig. 2 of Guide E844).5.4.2 Fission product production from photonuclearreactions, that
10、 is, (,f) reactions, while negligible near-powerand research-reactor cores, can be large for deep-water pen-etrations (1).45.5 Good agreement between neutron fluence measuredby238U fission and the54Fe(n,p)54Mn reaction has been dem-onstrated (2). The reaction238U(n,f) F.P. is useful since it isrespo
11、nsive to a broader range of neutron energies than mostthreshold detectors.5.6 The238U fission neutron spectrum-averaged cross sec-tion in several benchmark neutron fields is given in Table 3 ofPractice E261. Sources for the latest recommended crosssections are given in Guide E1018. In the case of th
12、e238U(n,f)F.P. reaction, the recommended cross section source is theENDF/B-VI release 8 cross section (MAT = 9237) (3). Fig. 1shows a plot of the recommended cross section versus neutronenergy for the fast-neutron reaction238U(n,f)F.P.NOTE 1The data is taken from the Evaluated Nuclear Data File,ENDF
13、/B-VI, rather than the later ENDF/B-VII. This is in accordance withGuide E1018, Section 6.1, since the later ENDF/B-VII data files do notinclude covariance information. Some covariance information existsfor238U in the standard sublibrary, but this is only for energies greaterthan 1 MeV. For more det
14、ails, see Section H of Ref 4.6. Apparatus6.1 Gamma-Ray Detection Equipment that can be used toaccurately measure the decay rate of fission product activity arethe following two types (5):6.1.1 NaI(T1) Gamma-Ray Scintillation Spectrometer (seeTest Methods E181 and E1005).6.1.2 Germanium Gamma-Ray Spe
15、ctrometer (see TestMethods E181 and E1005)Because of its high resolution, thegermanium detector is useful when contaminant activities arepresent.4The boldface numbers in parentheses refer to the list of references appended tothis test method.TABLE 1 Recommended Nuclear Parameters for Certain Fission
16、ProductsFissionProductParentHalf-LifeA(6)PrimaryRadiationA(7) (keV) ProbabilityofDecayA(7)MaximumUsefulIrradiationDuration95Zr 64.032 (6) d 724.192 (4) 0.4427 (22) 6 months756.725 (12) 0.543899Mo 65.94 (1) h 739.500 (17) 0.1213 (22) 300 hours777.921 (20) 0.0426 (8)103Ru 39.26 (2) d 497.085 (10) 0.91
17、0 (12) 4 months137Cs 30.05 (8) yr 661.657 (3)B0.8499 (20)B3040 years140Ba 140La 12.7527 (23) d 537.261 (4) 0.2439 (22) 11.5 months1596.21 (4) 0.9540 (8)C1.1515D144Ce 284.91 (5) d 133.515 (2) 0.1109 (19) 23 yearsAThe lightface numbers in parentheses are the magnitude of plus or minusuncertainties in
18、the last digit(s) listed.BWith137mBa (2.552 min) in equilibrium.CProbability of daughter140La decay.DWith140La (1.67855 d) in transient equilibrium.TABLE 2 Recommended Fission Yields for Certain FissionProductsAFissileIsotopeNeutronEnergyReactionProductTypeYieldJEFF-3.1.1A,BFission Yield %238U(n,f)
19、0.5 MeV95Zr RC 5.19 1.714 %99Mo RC 6.18 1.6 %103Ru RC 6.03 1.6 %137Cs RC 6.02 2.52 %137mBa RI 1.0169e-2 36.5 %140Ba RC 5.68 2.67 %140La RI 6.8165e-6 64 %144Ce RC 4.67 2.46 %AThe JEFF-3.1/3.1.1 radioactive decay data and fission yields sub-libraries, JEFFReport 20, OECD 2009, Nuclear Energy Agency.BA
20、ll yield data given as a %; RC represents a cumulative yield; RI represents anindependent yield.E704 1326.2 Balance, providing the accuracy and precision requiredby the experiment.6.3 Digital Computer, useful for data analysis (optional).7. Materials7.1 Uranium-238 Alloy or OxideHigh-purity238Uinthe
21、form of alloy wire, foil, or oxide powder is available.7.1.1 The238U target material should be furnished with acertificate of analysis indicating any impurity concentrations.7.2 Encapsulating MaterialsBrass, stainless steel, copper,aluminum, quartz, or vanadium have been used as primaryencapsulating
22、 materials. The container should be constructedin such a manner that it will not create significant perturbationof the neutron spectrum and fluence rate and that it may beopened easily, especially if the capsule is to be openedremotely. Certain encapsulation materials, for example, quartzand vanadiu
23、m, allow gamma-ray counting without opening thecapsule since there are no interfering activities.8. Procedure8.1 Select the size and shape of the sample to be irradiated,taking into consideration the size and shape of the irradiationspace. The mass and exposure time are parameters that can bevaried
24、to obtain a desired count rate for a given neutron fluencerate.8.2 Weigh the sample to the accuracy and precision requiredof the experiment; encapsulate; and, if irradiated in a thermalneutron environment, surround with a suitable high-meltingthermal neutron absorber.NOTE 2The melting point of eleme
25、ntal cadmium is 321C. Foradditional precautions, see Test Method E262.8.3 Irradiate the sample for the predetermined time period.Record the power level and any changes in power during theirradiation, the time at the beginning and end of each powerlevel, and the relative position of the monitors in t
26、he irradiationfacility.8.4 Check the sample for activity from cross contaminationby other monitors or material irradiated in the vicinity or fromany foreign substance adhering to the sample. Clean andreweigh, if necessary. If the sample is encapsulated oxidepowder and if it is necessary to open the
27、capsule, a suitablecontainment will be required.8.4.1 If chemical separation is necessary, dissolution can beachieved in 8 N HNO3-0.05 N HF.NOTE 3If an ion-exchange separation is to be subsequentlyperformed, follow the dissolution by fuming with sulfuric acid (H2SO4)toexpel fluorides. Fuming with H2
28、SO4, however, may expel volatile fissionproduct ruthenium, and, unless performed with care, losses of other fissionproducts by spattering can occur.8.5 Analyze the sample for fission-product content in dis-integrations per second (see Test Methods E181, E320, andE1005).8.5.1 It is assumed that the a
29、vailable apparatus has beencalibrated to measure F.P. activity and that the experimenter iswell versed in the operation of the apparatus.8.5.2 Disintegration of137Cs nuclei produces 0.661657-MeV gamma rays with a probability per decay of 0.8210. It isrecommended that a137Cs activity standard is used
30、.8.5.3 If the analyst is well versed in germanium countingand carefully calibrates the system, it is feasible to count137Cs-137mBa,140Ba-140La,95Zr, and144Ce directly without chemicalseparation.FIG. 1 ENDF/B-VI Cross Section Versus Energy for the238U(n,f)F.P. ReactionE704 1339. Calculation9.1 Calcul
31、ate the saturation activity, As, as follows:As5 A/y1 2 exp2ti!exp2tw!# (1)where: = disintegration constant for F.P., s1,A = number of disintegrations measured during the count-ing period, s1,ti= irradiation duration, s,tw= elapsed time between the end of irradiation andcounting, s, andy = fission yi
32、eld.NOTE 4This equation applies where transient equilibrium has beenestablished, is that of the parent species. This equation should not beapplied to the Ba/La line but can be applied to the other fission products.See Test Method E393 for reading the140Ba/140La line.NOTE 5The equation for Asis valid
33、 if the reactor operated atessentially constant power and if corrections for other reactions (forexample, impurities, burnout, etc.) are negligible. Refer to Practice E261for more generalized treatments.9.2 Calculate the reaction rate,5Rs, as follows:Rs5 As/No(2)where:No= number of target atoms.9.3
34、Refer to Practice E261 and Guide E944 for a discussionof the determination of fast-neutron fluence rate and fluence.10. Report10.1 Practice E261 describes how data should be reported.11. Precision and BiasNOTE 6Measurement uncertainty is described by a precision and biasstatement in this standard. A
35、nother acceptable approach is to use Type Aand B uncertainty components (8, 9). This Type A/B uncertainty specifi-cation is now used in International Organization for Standardization (ISO)Standards and this approach can be expected to play a more prominentrole in future uncertainty analyses.11.1 Gen
36、eral practice indicates that disintegration rates canbe determined with a bias of 6 5 % (1S %) and with aprecision of 61 % (1S %) (10).11.2 The238U cumulative fission product yields have anuncertainty between 0.7 % and 7.7 % (1S %) for the variousfission products as indicated in Table 1.12. Keywords
37、12.1 fission dosimeter; fission product; fission reactionrates; Uranium-238REFERENCES(1) Verbinski, V. V., et al, “Measurements and Calculations of Photofis-sion Effects in a Swimming Pool Type Reactor,” Transactions of theAmerican Nuclear Society, Vol 30, Washington, DC, November 1978.(2) Barry, K.
38、 M., and Corbett, J.A., “Measurement of Neutron Fluence byNeptunium-237 and Uranium-238 Fission Dosimeters,” NuclearTechnology, Vol 11, May 1971.(3) “ENDF-201, ENDF/B-VI Summary Documentation,” P. F. Rose, ed.,Brookhaven National Laboratory Report BNL-NCS-174, 4th Edition,October 1991.(4) “Special I
39、ssue on Evaluated Nuclear Data File ENDF/B-VII.0,”Nuclear Data Sheets, J. K. Tuli, ed., , Vol 107, December 2006.(5) Crouthamel, C. E. (Revised by Adams, F., and Dams, R.), AppliedGamma-Ray Spectrometry, Pergamon Press, 1970.(6) Nuclear Wallet Cards, compiled by J. K. Tuli, National Nuclear DataCent
40、er, October 2011.(7) Nuclear Data retrieval program NUDAT, a computer file of evaluatednuclear structure and radioactive decay data, which is maintained bythe National Nuclear Data Center (NNDC), Brookhaven NationalLaboratory (BNL), on behalf of the International Network for NuclearStructure Data Ev
41、aluation, which functions under the auspices of theNuclear Data Section of the International Atomic Energy Agency(IAEA).(8) Taylor, B. N., Kuyatt, C. E., “Guidelines for Evaluating and Express-ing the Uncertainty of NIST Measurement Results,” NIST TechnicalNote 1297, National Institute of Standards
42、and Technology,Gaithersburg, MD, 1994.(9) Guide in the Expression of Uncertainty in Measurements, Interna-tional Organization for Standardization, 1995, ISBN 9267101889.(10) Adams, J. M., “Results from the NIST Round Robin Test ofFissionable Dosimeters in a Reactor Leakage Spectrum,” ReactorDosimetr
43、y: Radiation Metrology and Assessment, ASTM STP 1389,American Society for Testing and Materials, West Conshohocken,PA, 2001ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expr
44、essly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revise
45、d, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may
46、attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United State
47、s. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).5Within the context of this test method, the terms “fission rate” and “reactionrate” can be used synonymously.E704 134
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